The present invention relates to an apparatus for punching steel studs to form holes of sufficient size to allow wiring and piping to extend therethrough, and sufficiently lacking sharp tongues or flanges that would damage the wiring or piping.
Steel frame homes and structures are becoming widespread. Steel frames have many advantages over traditional wooden frames. Steel frames are termite, rust, and rot proof. Further, steel frames are non-combustible, energy efficient, and resistant to poor weather and active seismic conditions.
Steel framing is made from light gauge galvanized steel cold formed into C-shaped cross-section components. Design changes are minimized by choosing components that match lumber dimensions, particularly when converting a wooden frame design to a steel frame design. Studs come in all sizes; however, most builders use 3⅝ inch and 5xc2xd inch sizes that match wood frame dimensions.
When building steel frame homes and structures, it is necessary to have holes punched in the studs. These punched holes, sometimes called knock-outs, accommodate plumbing and electrical wiring by allowing pipes and/or wires to run through the holes. Steel studs may be purchased with preformed holes. Many times, the preformed holes are not in the desired locations, or there are no preformed holes. In these situations, the builder must form the holes in the steel stud wherever the holes are needed.
One way to form these holes is to use an acetylene torch to cut the holes. Using an acetylene torch to cut holes in steel studs is inconvenient for a builder. Another way to form holes in steel studs is with a large mechanical lever type piercer and die tool, such as that described in U.S. Pat. No. 5,287,716 issued to Szulc. Because a builder may not realize where it is desired to form holes in the steel studs until the frame is at least partially constructed, forming the holes is difficult. Many times, it is not possible to position the large lever type tool about the steel frame to form the holes because of the large size of the lever type tool, and because of the space constraints of the partially constructed frame. Further, sometimes it is difficult to align the holes on adjacent studs such that piping may be routed therethrough without additional difficulties. Still further, smaller lever type tools are generally only useful for forming small holes such as screw holes, and are not designed to form holes sized for wiring and/or piping.
It is, therefore, an object of the present invention to provide a compact hand held apparatus for punching steel studs.
In carrying out the above object, an apparatus for punching knock-outs out of light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough is provided. The apparatus comprises a compact hand held frame having a generally C-shaped portion with spaced apart ends located along a working axis, and a handle for gripping by a user. A punch and die assembly includes a punch and a die mounted opposite each other at the ends of the C-shaped frame portion. The punch and the die are mounted for movement relative to each other along the working axis. An actuatable driving mechanism is mounted to the frame. The driving mechanism is operable to drive the punch and die assembly over a working stroke range between a deactuated and an actuated position. In the deactuated position, the punch and the die are spaced apart with the stud positioned therebetween. In the actuated position, the punch extends into the die cavity by punching through the stud to form the punched hole.
In a preferred embodiment, the working stroke range is not significantly larger than that required to punch through the stud. A gross adjust mechanism is configured for moving the punch and the die relative to each other over a gross adjust stroke range significantly larger than that required to punch through the stud between an open position and a closed position. The open position allows the positioning of the stud between the punch and the die. The closed position is based on the working stroke range to cause punching of the punch through the stud upon actuation of the driving mechanism.
Further, in a preferred embodiment, the C-shaped frame portion includes first and second halves. Each half includes a respective end of the C-shaped frame portion. The gross adjust stroke range is defined along the working axis. The gross adjust mechanism includes a slide member connecting the first and second halves of the C-shaped frame portion. The slide member allows movement of the die toward and away from the punch along the working axis. The gross adjust mechanism further includes a lock device for unlocking the slide member to allow movement of the slide member, and for locking the slide member to prevent movement of the slide member during actuation of the driving member.
Preferably, both ends of the C-shaped frame portion include undercut jaw portions to allow positioning of differently shaped studs between the punch and the die.
Further, in carrying out the present invention, an apparatus for punching knock-outs out of light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough comprises a compact hand held frame, a punch and die assembly, and a gross adjust mechanism. The gross adjust mechanism includes a shaft oriented along the working axis and having first and second ends. A punch is mounted to the shaft first end, and the shaft slidably cooperates with the frame to move the punch relative to the die over the gross adjust stroke range between the open and closed positions. A driving mechanism comprises a lever pivotally attached to the frame, and having a grip portion proximate the handle enabling the user to squeeze the handle and lever together. An advance sear cooperates with the shaft and the lever to cause the shaft to incrementally advance the punch toward the die each time the lever grip portion is squeezed toward the handle. A retract sear cooperates with the shaft and the frame to enable the shaft to freely advance while preventing the shaft from retracting after each incremental advance.
The advantages accruing to the present invention are numerous. For example, embodiments of the present invention provide a compact hand held tool for punching steel studs to form holes of sufficient size to allow wiring and piping to extend therethrough. Further, the gross adjust mechanism and undercut jaws provide tool versatility, particularly for punching holes in steel studs which are already secured within a partially constructed frame. Preferably, the punch is configured with respect to the die cavity such that punching the hole produces a knock-out. Still further, it is preferred that an annular gap between the punch and the die cavity, when the punch is extended into the die cavity, is sufficiently small such that the punched hole is substantially flangeless. That is, the hole sufficiently lacks sharp tongues or flanges that would damage the wiring or piping.